实现深拷贝

function deepClone(val) {
    const type = getType(val);
    // 如果不是数组或对象，不需要递归，则直接返回
    if (type !== 'Array' && type !== 'Object') {
        return val;
    }
    // 如果是数组或对象，构造一个新的，遍历复制
    let res = type === 'Object' ? {} : [];
    for (let key in val) {
        const subVal = val[key];
        const subType = getType(subVal);
        if (subType !== 'Object' && subType !== 'Array') {
            res[key] = subVal;
        } else {
            res[key] = deepClone(subVal);
        }
    }
    return res;
    // 获取类型工具函数
    function getType(val) {
        return Object.prototype.toString.call(val).slice(8, -1);
    }
}
// const arr1 = [1, 2, 3, 4, 5]
// const arr2 = deepClone([1, 2, 3, 4, 5])
// arr1[1] = 10
// console.log(arr1, arr2)
const obj1 = { a: 1, b: 2, c: 3, d: 4, e: { a: 1, b: 2, c: 3 } }
const obj2 = deepClone(obj1)
obj1.e.a = 1000
console.log(obj1, obj2)

参考
https://www.cxymsg.com/guide/jsWritten.html#%E5%AE%9E%E7%8E%B0%E9%98%B2%E6%8A%96%E5%87%BD%E6%95%B0%EF%BC%88debounce%EF%BC%89
https://www.yuque.com/chenyubo/knowledge-map/qus818#OP8CP